Noguchi Ryo, Kobayashi Masaru, Jiang Zhanzhi, Kuroda Kenta, Takahashi Takanari, Xu Zifan, Lee Daehun, Hirayama Motoaki, Ochi Masayuki, Shirasawa Tetsuroh, Zhang Peng, Lin Chun, Bareille Cédric, Sakuragi Shunsuke, Tanaka Hiroaki, Kunisada So, Kurokawa Kifu, Yaji Koichiro, Harasawa Ayumi, Kandyba Viktor, Giampietri Alessio, Barinov Alexei, Kim Timur K, Cacho Cephise, Hashimoto Makoto, Lu Donghui, Shin Shik, Arita Ryotaro, Lai Keji, Sasagawa Takao, Kondo Takeshi
Institute for Solid State Physics, The University of Tokyo, Kashiwa, Japan.
Materials and Structures Laboratory, Tokyo Institute of Technology, Yokohama, Japan.
Nat Mater. 2021 Apr;20(4):473-479. doi: 10.1038/s41563-020-00871-7. Epub 2021 Jan 4.
Low-dimensional van der Waals materials have been extensively studied as a platform with which to generate quantum effects. Advancing this research, topological quantum materials with van der Waals structures are currently receiving a great deal of attention. Here, we use the concept of designing topological materials by the van der Waals stacking of quantum spin Hall insulators. Most interestingly, we find that a slight shift of inversion centre in the unit cell caused by a modification of stacking induces a transition from a trivial insulator to a higher-order topological insulator. Based on this, we present angle-resolved photoemission spectroscopy results showing that the real three-dimensional material BiBr is a higher-order topological insulator. Our demonstration that various topological states can be selected by stacking chains differently, combined with the advantages of van der Waals materials, offers a playground for engineering topologically non-trivial edge states towards future spintronics applications.
低维范德华材料作为一种产生量子效应的平台已得到广泛研究。在此研究基础上，具有范德华结构的拓扑量子材料目前正受到广泛关注。在这里，我们运用通过量子自旋霍尔绝缘体的范德华堆叠来设计拓扑材料的概念。最有趣的是，我们发现由堆叠修改引起的晶胞中反演中心的轻微移动会导致从平凡绝缘体到高阶拓扑绝缘体的转变。基于此，我们给出了角分辨光电子能谱结果，表明真实的三维材料溴化铋是一种高阶拓扑绝缘体。我们证明了可以通过不同方式堆叠链来选择各种拓扑态，再结合范德华材料的优点，为面向未来自旋电子学应用设计拓扑非平凡边缘态提供了一个平台。
